1. Technical Field
The present invention relates to a pattern formation device.
2. Related Art
An inkjet device, i.e., a droplet discharge device, for discharging a functional liquid in the form of droplets is commonly known as a pattern formation device for forming a desired pattern on a substrate using a functional liquid. The droplet discharge device forms a pattern by arranging droplets of a functional liquid discharged from a droplet discharge head in arbitrary locations on a substrate while moving the substrate mounted on a stage and the droplet discharge head for discharging droplets of the functional liquid relative to each other in two dimensions.
A droplet discharge device has recently been applied in which a plurality of droplet discharge heads is mounted on a single carriage, and a plurality of carriages is furthermore provided. Such a droplet discharge device is used for large-screen color filter manufacturing and the like, and the drawing speed thereof is enhanced by aligning a plurality of carriages and discharging droplets at the same time.
When the droplet discharge head is discharging, the drive elements and the like provided inside the droplet discharge head give off heat as a result of operation. This heat causes the air around the carriage or the functional liquid inside the droplet discharge head to increase in temperature. It is known that the discharge quantity of droplets from the droplet discharge head also varies according to variation in the viscosity of the functional liquid that accompanies increased temperature of the functional liquid. The droplet discharge device is therefore operated in a clean room in which air-conditioned air (down-flow) is fed from above so that the cleanliness of the area around the substrate is maintained during drawing, and so that the temperature in the room is constant.
The droplet discharge device having a plurality of carriages installed therein as described above is provided with a carriage plate that is positioned across the two guide rails so as to be able to move, and the carriages in which the droplet discharge heads are mounted are provided to the underside of the carriage plate. This structure therefore makes it difficult for a down-flow to be fed to the area around the carriages and droplet discharge heads. In other words, air that is heated by the heat of the droplet discharge heads stagnates in the area around the carriages, which leads to further heating of the droplet discharge heads, and a uniform discharge quantity is impossible to obtain. Japanese Laid-Open Patent Application No. 9-153530 discloses a method for creating a horizontally directed air flow in a clean room in a device having such a structure in which down-flow is blocked.